Embryonic stem (ES) cells can survive and differentiate after transplantation into the adult brain and can potentially be used to promote repair and restore function in the damaged brain. This proposal will explore the possible role of bcl-2 overexpression in enhancing the survival and regenerative potential of ES cells transplanted into rats following barrel cortex ischemia. This system provides a unique model for assessing ES cell effects on angiogenesis and whisker-barrel architecture and function. Specific Aim 1 will compare the effects of bcl-2 over-expression on survival and differentiation of ES cells transplanted into the ischemic barrel cortex. The optimal number of ES cells with and without bcl-2 overexpression to achieve the best survival and differentiation will be determined. Specific Aim 2 will examine whether the improved survival and increased differentiation achieved in Aim 1 will result in greater regenerating potential as demonstrated by morphological (neuronal connections, synapse formation, enhanced angiogenesis) and functional (regional cerebral blood flow, whisker activity-induced optical signals, glucose metabolism, electrical activities) criteria. Specific Aim 3 will explore whether the best strategy for regeneration achieved in Specific Aims 1 and 2 can be further improved by preferential afferent whisker input to the injured barrel cortex. This proposal aims to advance ES cell transplantation strategies beyond the current approaches in an attempt to maximize the regenerating potential.